That's the name of a new cartoon strip I've invented.
In the first strip two echidnas are poring over a trigonometry problem. You can see it's a maths book and you know from the title it's trigonometry, right? They do that for three panels, looking puzzled, and then in the fourth one echidna says to the other, 'Dude, I think you meant Sine, not Cosine.'
You have to think about it for a minute, and then you laugh. Except you are wrong: it's not funny. I just did that to test you!